1. Field of the Invention
The present invention relates to footwear. In particular the present invention is related to strapping systems for securely affixing footwear to a user""s foot.
2. Background of the Invention
There is a wide variety of prior art showing strapping configurations for footwear. Generally, the purpose of such strapping has mainly been to secure the footwear to a user""s foot.
Examples of prior art showing footwear strapping arrangements include U.S. Pat. Nos. 4,200,997 and 4,446,633 to Scheinhaus, U.S. Pat. No. 4,817,302 to Saltsman, U.S. Pat. No. 4,300,294 Riecken, U.S. Pat. No. 2,788,591 to Gibson, U.S. Pat. No. 2,126,094 to Daniels, and U.S. Pat. No. 2,862,311 to Ellis. Each of these patents disclose a strapping configuration which may be used in closed and open footwear which engages the ankle, heel, instep, toes, arch, or some combination thereof to secure the footwear to the user""s foot. None of these prior art disclosures, however, nor any other existing strapping configurations have been entirely satisfactory in securing footwear to the foot while providing support and maintaining a comfortable, durable, and convenient configuration.
One particular problem relates to ankle straps. As the angle between the foot and the ankle changes during normal walking or running, the foot""s main tendon that travels down the front of the leg and across the instep of the foot is cyclically tightened and loosened. This causes the overall circumference of the ankle and instep to increase and decrease. It is helpful for strapping systems which wrap the ankle to allow for this expansion and contraction. Most closed footwear either does not include ankle straps or does not allow for contraction and expansion of the ankle.
Another problem results from the use of strapping configurations that have only limited contact with foot sections. For instance, some prior strapping configurations contact the foot only along a transverse axis. As forces associated with foot movement may occur along the longitudinal axis of the foot, as well as in all other directions, such transverse oriented strapping is limited in its ability to secure the foot to the sole. Balance, comfort and convenience are also limited.
Indeed, prior footwear straps are typically oriented in a direction that does not correspond to the force vectors that occur during walking, running, or other activity. Strapping usually is oriented at an angle of approximately 90xc2x0 from the sole. This angle contributes to maximizing strapping strength, but generally only when the strap lies flat and parallel to the sole on the foot surface. As the top of the foot slopes forward, however, a strap oriented at a 90xc2x0 angle from the sole must twist to lie flat on the sloping foot surface. This can cause discomfort in the user and diminish the strength of the strap.
During normal walking or running, the foot generally moves in an upward and forward motion, and correspondingly pulls the sole in this direction. A strap oriented at a 90xc2x0 angle to the sole, however, is positioned to be at its peak strength and comfort to the user for forces directed straight upwards from the sole. These straps are therefore disadvantageous for use with a natural foot movement.
Another problem existing with many prior art closed footwear strapping configurations is the point of connection of the strapping to the sole. Strapping that is connected at isolated points generally only secures the foot to these isolated points. Often, the point of stress is at the surface of the sole and tends to be near the sole front or rear edges. Because the sole is inherently flexible, securing strapping to these isolated, static points inevitably leads to bending and unequal movement of the sole with reference to the foot, particularly during vigorous foot movement.
Other prior strapping configurations do not allow for natural movement of the foot to occur during sports or the like. While these configurations may secure the sole to the foot when stationary, they are incapable of adjusting as the foot may change shape slightly during movement. In addition, they are not well suited to accommodating forces occurring in a variety of directions during vigorous activity.
Still other prior art footwear strapping configurations feature a continuous strap that contacts the wearer""s foot in multiple locations, such as around the ankle, across the instep, and over the front of the foot. Such straps cannot be snugly fit to a single portion of the wearer""s foot, as they must allow for movements of other portions of the foot. A continuous strap that covers both the instep and the forefoot, for instance, may develop looseness over the instep due to movement of the forefoot.
Numerous unresolved needs therefore exist relating to footwear. A need exists for a footwear strapping configuration that securely fixes the sole to the foot and accommodates the wide range of forces developed during sports or other vigorous activities. In addition, a need exists for strapping that is capable of dynamically adjusting itself as required during such use.
The present invention comprises a unique strapping configuration for footwear that provides for dynamic fit adjustment while securely and comfortably affixing a sole to a wearer""s foot. In accordance with one exemplary embodiment of the present invention, the strapping comprises one or more straps suitably configured to create an adjustable X configuration which crosses over the wearer""s instep. The strapping configuration preferably passes through a transverse channel in the midsole of the footwear under the wearer""s arch. The present invention further comprises closed footwear incorporating the unique strapping configuration that securely fastens the footwear to the user""s foot, even during sports or other vigorous activities.
The adjustable X configuration instep strap generally has a first end secured to a first side of the heel portion of the footwear, crosses forwardly and transversely over the wearer""s instep, passes through a channel in the sole of the footwear at the midfoot, the longitudinal center of the sole, extends rearwardly and transversely back across the wearer""s instep (thereby forming an X over the instep), and is adjustably and releasably secured to the second side of the heel portion of the footwear. Preferably, the channel is angled downwardly from rear to front in the longitudinal direction, parallel to the downward slope of the wearer""s instep, so that the strap will lie flat on the wearer""s instep and thereby more evenly carry forces that develop between the foot and the sole during sports or other vigorous activities.
The X configuration instep strap acts to secure the entire circumference of a wearer""s foot to the footwear sole. In the preferred embodiment, the strap passes under the wearer""s arch through the midfoot channel, and thereby works to secure the entire transverse midfoot portion of the sole to the bottom of the wearer""s foot. Further, as the strap passes through the channel it similarly operates to force the sole upward from near its center of gravity.
In an alternative embodiment of the present invention, multiple straps may be provided for creating the X configuration, rendering the midfoot channel optional. The straps are secured to the medial and lateral sides of the footwear, again crossing over the instep to provide the X configuration.
The present invention encompasses various footwear designs incorporating the aforesaid X-strap. For example, the footwear of the invention comprises open footwear such as a sandal. However, the present invention may also include closed footwear, such as hiking boots, skates, basketball shoes, and the like. In this regard, it is to be understood that as used herein the term xe2x80x9cfootwearxe2x80x9d is intended to encompass closed footwear such as running and basketball shoes, hiking boots, in-line skates, ice skates, ski boots, snowboard boots, and the like.